Investigation of probiotic use among inpatients at an academic medical center

Background: Probiotic use has become very common; related infections have been described in immunosuppressed patients and those with impaired intestinal integrity. Certain probiotic package inserts now contain warnings regarding their use in such patients. Probiotics have been non-formulary at our institution, and since 2008 there has been a moratorium against their use.

Objective: We sought to evaluate the use of all Lactobacillus oral supplements among inpatients at our tertiary care medical center over a 9 year period, and to determine the incidence of Lactobacillus bacteremia among these patients. We also assessed the use of probiotics among immunosuppressed and intestinally impaired patients over a 1 year period.

Methods: Lactobacillus positive blood cultures in inpatients between10/2000 and 10/2009 were identified. Probiotic-related bacteremia included any patient taking Lactobacillus within a month prior to positive culture. Charts of inpatients on Lactobacillus from 8/2007 to 8/2008 were assessed for immunosuppression stratification. Patients were mildly immunosuppressed (MI) if they met one of the following: ≥ 80 years old, chronic kidney disease (CKD), diabetes mellitus (DM), or cirrhosis. Moderately immunosuppresed criteria were HIV+ (CD4>200 mm³), use of systemic steroids, or ≥2 of the MI criteria. Severely immunosuppresed criteria included history of transplant, AIDS (CD4<200mm³), neutropenia (ANC<1,000) or history of hematological malignancy. Intestinal abnormalities were defined as history of inflammatory bowel disease (IBD) or abdominal imaging with colitis, bowel thickening or distention within 2 weeks of taking probiotics.

Results: A total of 1224 inpatients received L. acidophilus/L. bulgaricus over 9 years. This represents an annual institutional prescribing rate of 136 prescriptions/81,766 admissions (0.17%). The associated yearly hospital expenses were $3,500. 2 cases of probiotic-related Lactobacillus bacteremia were identified over the 9 year period; both were treated with broad spectrum antibiotics with Lactobacillus coverage for unrelated concurrent infections, and both improved.

350 charts of inpatients on Lactobacillus probiotics between 8/2007 and 8/2008 were reviewed. The mean age and Charlson score were 66±18 years and 3.1±2.7, respectively. 30% had mild, 30% had moderate and 10% had severe immunosuppression; 26% were found to have intestinal abnormalities.

Conclusions: Despite non-formulary status, probiotics were still used at our center, with Lactobacillus being the probiotic of choice. Probiotic use was common in patients with moderate to severe immunosuppression and in patients with impaired intestinal immunity. Even though the incidence of related bloodstream infections was low, these cases could have been prevented.